hot-backup.py: Modernize Python syntax.
hot-backup.py: Modernize Python syntax.

* tools/backup/hot-backup.py.in: Drop syntaxes unsupported by ≥py3.0, while
    retaining compatibility with ≥py2.6.  (Both trunk and 1.9.x require ≥py2.7.)


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1721179 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion